The microbending of an optical fiber has been considered a simple and rugged design approach for a highly sensitive motion detector. The components required for such a device are simple, inexpensive and easily obtained. All that is required is one optical fiber, a light source (such as an LED) and detector with associated control electronics, and a means of modulating the bends in the fiber. In order to take advantage of the sensitivity of the microbend approach, mechanical designs that take full advantage of the large dynamic range and the minute displacements involved must be considered. At the same time, the mechanical and optical limitations of the sensing mechanism must be dealt with.
Sensors employing microbend technology are known in the art and reference is made to the Macedo et al U.S. Pat. No. 4,342,907.
Fiber optic accelerometers are also known and the Davis et al Pat. No. 4,322,829 is an example, as is the Nissl Pat. No. 4,226,120.
SUMMARY OF THE INVENTION
The fiber optic microbend accelerometer of the invention may be generally defined as including a rigid housing, a beam connected at one end to the housing, and a mass connected at the other end of the beam, the connected mass being free to move within the housing upon application of force to the housing in a direction normal to the plane of the beam. A pair of fiber deforming teeth sets mounted in opposed relation, one to the mass and the other to the housing, and an optical fiber positioned between the pair of teeth sets and in contact with the teeth.